This invention relates to current-limiting circuit interrupters, and more specifically relates to a novel adapter for a current-limiting circuit interrupter which permits the addition of one or more current-limiting breaks in series with the contacts of a conventional current-limiting circuit interrupter.
A current-limiting circuit breaker assembly including a main circuit breaker having a current-limiting pair of contacts and an adapter affixed to the main circuit breaker also having a pair of current-limiting contacts is disclosed in U.S. Pat. No. 4,346,357 which issued on Aug. 24, 1982 to Frank W. Kussy et al. and assigned to the assignee of the present invention. The pair of contacts contained in the circuit breaker adapter are designed to interrupt major faults only, i.e. faults on the order of at least ten times the rated current of the circuit and up to, in some circumstances, several thousand times the rated current of the circuit. The present invention recognizes the problem that at the low end of the above-noted fault range--the point at which the contacts in the adapter will begin to electromagnetically repel one another--that it is desirable to prevent welding of the contacts. The present invention further recognizes that in such current-limiting circuit breaker assemblies it is desirable to permit the circuit breaker adapter to be affixed to the main circuit breaker in such a manner that it can be easily added in the field.